“Stone of Sisyphus,” the title track from a deleted album recorded just after Chicago’s heyday as a slick power-ballad act, gained grail-like mystery when the band’s label scrapped the project for being too adventurous.

Well, back then, I guess.

What you end up with is an uncommercial release that’s still too safe to be called experimental. This no-man’s-land dichotomy plays out in high relief here, one of the record’s most successful efforts.

“Stone of Sisyphus,” the song, stands as both a reminder of what Chicago — which has sold more than 122 million recordings, boasted five consecutive No. 1 albums and notched more than 50 Top-40 singles — once was … and a confirmation of what it apparently will never be again.

Lead vocals on this 1993 recording are by founding singer/pianist Robert Lamm and former guitarist Dawayne Bailey, with a writing assist from horn-playing stalwart Lee Loughnane. Also prominently featured are Chicago’s so-called new guys, vocalist/guitarist/keyboardist Bill Champlin (at that point in the group since 1981) and bassist/vocalist Jason Scheff (who joined in 1985).

It says something about the longevity of this band, and how hard it must have been to break out of the creative inertia that comes with age, when the junior members have tenures dating back to the Reagan administration.

The muscular brass, driving rhythms and inventive song structure so closely associated with Chicago’s definitive (that is, late 1960s and early ’70s) period drift back in — and so, then, does this sense of what the group, though in a late-career slumber, could still accomplish.

Even in this valiant effort, though, there is too much polish — the fault, it seems, of the times and their producer. Peter Wolf pushed Chicago to (at least relatively) creative places, but he was still a guy who had come to fame working with Starship, the washed-out final bubble-gum gasps of one of San Francisco’s most important ’60s-era rock bands.

“Stone of Sisyphus” doesn’t go far enough to be truly jazzy, and isn’t hard enough to be called rock — things you could always say (often in the same song) during the Terry Kath-dominated early years.

Instead, it boasts a familiar, if obvious, listenability that stuck with Chicago — even as their creativity failed them. That’s why this isn’t the kind of artistic leap that required shelving. To be honest, “Stone of Sisyphus” actually marks the initial salvo in a record — eventually issued as a Rhino release this summer — that is, on balance, instantly recognizable by period for anyone who owned a radio during Chicago’s reign as mainstream pop music’s principal proprietor of middle-of-the-road makeout music. (Something, by the way, that began long before David Foster joined the proceedings.)

So, should it be enough that “Stone of Sisyphus” is a step up from the creeping commercialism (including a series of hollow contemporary tunes written by hired-gun Dianne Warren) then choking the life out of Chicago? Had it gotten so bad that we were reduced to praising this track, and Chicago, simply for trying?

Depends on your devotion to the group.

Chicago never actually answered the question of where it was headed, instead following up this shelved effort with a successful, if stubbornly nostalgic, album of jazz standards two years later.

That makes this song’s title, taken from a character in Greek mythology who pushes a heavy stone up a hill only to have it roll back down for eternity, all the more sadly ironic.

Nick DeRiso has written for USA Today, American Songwriter, All About Jazz, and a host of others. Honored as columnist of the year five times by the Associated Press, Louisiana Press Association and Louisiana Sports Writers Association, he oversaw a daily section named Top 10 in the U.S. by the AP before co-founding Something Else! Nick is now associate editor of Ultimate Classic Rock.